Dental alloy



. am. a. a,- 1943 UNITED sTA'rEs PATENT o -"Pica v 2,304.43 y 'nnn'rar.also! 3 Iosef Deuser, Pforsheim, Germany, assignor to Chemical MarketingCompany In, New vYork. .9 N. Y., a corporation of New York No Drawing.Application September 12, 1940, Se-

rial No. 356,562. in Germany August 25, 1939 .3 Claims.

In dentistry gold alloyswith at least 75% gold or gold plus platinummetal alloys are employed for orthodontic parts which must stand greatstress. In these alloys which contain gold and a platinum metal a highpercentage of precious metals was deemed necessary to secure asufficient resistance against corrosion in mouth. Be-

sides gold and platinum metals thesealloys contain also silver, copperand, if desired, zinc, nickel, tin and other base metals. The content ofplatinum metals was increased up to 20% and more to procure thedesiredstrength, tenacity and durability of these alloys. The alloys havenearly almost a white color.

To reduce the cost price palladium silver alloys with small additions ofgold and platinum as well aspale yellow alloys with a content of about50% gold and several percent of palladium have also been used. Thesealloys possess the necessary strength, but not the tenacity anddurability which are indispensable for numerous purposes in dentistry orthey are very dliilcult to work. Now I have found that alloys with 60 to70% of gold and platinum metals have an extraordinarily high strength,tenacity and durability, if

at least two platinum metals, preferably platinum and palladium, areused together. They are also very resistant against the influences ofthe mouth liquids. Thereby the content of platinum may exceed that ofpalladium but the palladium content should not be less than 1% of thewhole alloy. Such alloys have an excellent hardness andstrength. Theyare easy to work and to roll and may also be subjected towire drawing.Their fusion point is advantageous and enables an easy casting. Theirtenacity and alternating bending strength in a tempered and slowly.cooled condition is very remarkable. This is especially important withrespect to the use in dentistry. Furthermore, these alloys have provedresistant against tarnishing as well as against all aggressive agentswhich may be present in the mouth. The alloys have a pale yellow orgolden tinted color The following table describes the variouscompositions and qualities of the alloys:

Per cent Number Brineli oibends hardness, wire Au Pt Pd Ag Cu Zn Q? 55'2 6 11.5 0.5 137 1B 5 2 N 11.5 0.5 106 18 55 l 0 2 22 11.5 0.5 1% 23 e05 5 l5 l4 1 109 18 67 4 3 14.5 ll 0.5 183 15 3 2 13.5 9.5 2 l 146 16 Thealloys according to my invention may be used in dentistry for all partswhich undergo a high stress such as, for instance, clasps, orthodonticappliances, root pins, tooth pins and the like. u 7

WhatI claim is: l

1. Dental alloy consisting of 55% gold, 2% platinum, 6% paladium,11.5%00Plfil. 0.5% nine, 25% silver.

'2. Dental alloy consisting of 55% gold, 9% platinum, 2% palladium,11.5% copper, 0.5% zinc, 22% silver.

3. A dental alloy consisting of,50% to 10% of gold, 2% to 9% ofplatinum, 1% to 6% of palladium, to 15% of copper, 0.1% to 2% of sins,and the remainder substantially all silver, the silveroonstituting13.5%to 26% of the alloy.

Joan-moan.

